Monday, September 11, 2023

Major Hurricane Lee (Category 3), Is Increasingly Likely To Impact Our Region Update One











































548 
WTNT33 KNHC 120248
TCPAT3

BULLETIN
Hurricane Lee Advisory Number  27
NWS National Hurricane Center Miami FL       AL132023
1100 PM AST Mon Sep 11 2023

...LEE IS A LARGE MAJOR HURRICANE EXPECTED TO SLOWLY TURN
NORTHWARD LATER THIS WEEK...
...HAZARDOUS SURF AND RIP CURRENT CONDITIONS EXPECTED AT BEACHES
ACROSS THE WESTERN ATLANTIC ALL WEEK...

SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.9N 64.8W
ABOUT 410 MI...655 KM NNW OF THE NORTHERN LEEWARD ISLANDS
ABOUT 580 MI...935 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...948 MB...28.00 INCHES

WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in Bermuda should monitor the progress of Lee.

DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Hurricane Lee was located 
near latitude 23.9 North, longitude 64.8 West. Lee is moving toward 
the west-northwest near 7 mph (11 km/h). A slow west-northwest to 
northwest motion is expected during the next day or two, followed by 
a turn toward the north by midweek. On the forecast track, Lee is 
expected to pass near, but to the west of Bermuda in a few days.

Maximum sustained winds are near 115 mph (185 km/h) with higher
gusts.  Lee is a category 3 hurricane on the Saffir-Simpson
Hurricane Wind Scale.  Some slight strengthening is forecast in the 
next day or so, followed by gradual weakening. 

Lee remains large with hurricane-force winds extending outward up 
to 80 miles (130 km) from the center and tropical-storm-force winds 
extending outward up to 185 miles (295 km). Saildrone 1064, located 
about 40 miles south-southeast of Lee's center, reported a sustained 
wind of 77 mph (124 km/h) and a wind gust of 105 mph (170 km/h) in 
the last few hours.

The estimated minimum central pressure is 948 mb (28.00 inches). 
Saildrone 1064 also reported a minimum pressure of 964 mb     
(28.46 inches) in the last few hours.

HAZARDS AFFECTING LAND
----------------------
Key messages for Lee can be found in the Tropical Cyclone Discussion
under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC and on the
web at hurricanes.gov/text/MIATCDAT3.shtml

SURF:  Swells generated by Lee are affecting portions of the Lesser
Antilles, the British and U.S. Virgin Islands, Puerto Rico,
Hispaniola, the Turks and Caicos Islands, the Bahamas, and Bermuda.
These swells are likely to cause life-threatening surf and rip
current conditions. Dangerous surf and rip currents have begun to
affect portions of the southeastern U.S. coast, and these conditions
are forecast to spread northward along much of the U.S. East Coast
during the next day or two. Please consult products from your local
weather office.


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Papin



000
WTNT43 KNHC 120253
TCDAT3

Hurricane Lee Discussion Number  27
NWS National Hurricane Center Miami FL       AL132023
1100 PM AST Mon Sep 11 2023

This evening, Lee appears to be in the final stages of completing 
another eyewall replacement cycle (ERC). A GPM microwave pass at 
2201 UTC showed that the outer eyewall remains closed and, while it 
remains quite large, continues to contract slowly as the inner 
eyewall decays within. The initial intensity is held at 100 kt this 
advisory, blending the subjective and objective intensity estimates 
this evening. Another Air Force Reserve Reconnaissance mission is 
scheduled to investigate the storm overnight, and several saildrones 
along Lee's path are also likely to provide additional in-situ 
observations in the hurricane over the next day or so.

Lee continues to move slowly west-northwestward, with the motion 
estimated at 295/6 kt. Lee is expected to continue moving slowly 
west-northwest or northwest over the next 24-36 h while mid-level 
ridging remains in place centered northwest of the hurricane. 
However, the ridge should then become eroded and shift eastward as a 
mid- to upper-level trough swings into the northeastern United 
States. This pattern change should result in Lee turning northward 
and gradually accelerating. The biggest spread in the track 
guidance solutions remains in the along-track direction, with the 
GFS on the faster end, and ECMWF on the slower end. The NHC track 
forecast continues to favor a blend of the simple and corrected 
consensus aids, and is very close to the previous forecast track 
through 72 h, and is just a touch east of the prior track 
thereafter. On this track, Lee is likely to pass near, but west of, 
Bermuda late Thursday and Friday and then be situated offshore of 
the mid-Atlantic states and New England late Friday and Saturday.

With the pending completion of Lee's ERC, expected over the next 
6-12 hours, the NHC intensity forecast continues to show some modest 
re-intensification. This seems reasonable given that sea surface 
temperatures (SSTs) observed by a saildrone in Lee's south outer 
eyewall are still around 29 C. After the next day or so, however, 
coupled atmospheric-ocean models suggest the large wind field of Lee 
will begin to upwell cooler SSTs, and Lee is still forecast to move 
over a cool SST wake left behind by Hurricanes Idalia and Franklin 
later this week. In addition, the approaching mid-latitude trough 
should also result in an increase in shear, and dry air entrainment, 
which should result in more steady weakening later this week and 
over the weekend. This trough interaction will also ultimately lead 
to Lee transitioning to an extratropical cyclone by the end of the 
forecast period as it crosses the north wall of the Gulf Stream. The 
NHC intensity forecast is a bit lower than the prior cycle after 72 
h but remains close to the consensus intensity aids.

Although Lee is expected to weaken later in the week, it is still 
expected to significantly increase in size and hazards will extend 
well away from the storm center by the end of the forecast period.

KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. Lee could bring strong winds, rainfall, and high surf impacts to
Bermuda later this week. Interests there should continue to monitor
updates to the forecast of Lee during the next several days.

3. It remains too soon to know what level of additional impacts Lee 
might have along the Northeast U.S. coast and Atlantic Canada late 
this week and this weekend.  However, because wind and rainfall 
hazards will likely extend well away from the center as Lee grows in 
size, users should continue to monitor updates to Lee's forecast 
during the next several days.

FORECAST POSITIONS AND MAX WINDS

INIT  12/0300Z 23.9N  64.8W  100 KT 115 MPH
 12H  12/1200Z 24.4N  65.6W  105 KT 120 MPH
 24H  13/0000Z 25.0N  66.5W  105 KT 120 MPH
 36H  13/1200Z 26.1N  67.2W  100 KT 115 MPH
 48H  14/0000Z 27.5N  67.6W   95 KT 110 MPH
 60H  14/1200Z 29.4N  67.9W   90 KT 105 MPH
 72H  15/0000Z 31.6N  67.8W   80 KT  90 MPH
 96H  16/0000Z 37.6N  66.4W   70 KT  80 MPH
120H  17/0000Z 43.0N  66.0W   60 KT  70 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin


000
FXUS61 KCAR 120121
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
921 PM EDT Mon Sep 11 2023

.SYNOPSIS...
A frontal boundary will move south across the Gulf of Maine
tonight. An occluded front will approach late Tuesday through
Tuesday night, then cross the region Wednesday through early
Thursday. High pressure returns on Friday. Hurricane Lee
slowly approaches south of the Gulf of Maine by Saturday.
Continue to monitor National Hurricane Center products for the
latest information on the strength/track/timing of Hurricane
Lee......

A frontal boundary will remain nearly stationary along the
Downeast coast early tonight. The frontal boundary will then
settle south across the Gulf of Maine overnight while low
pressure moves along the front. Expect numerous showers across
Downeast areas tonight. Shower chances diminish northward across
the remainder of the forecast area, with generally only cloudy
skies expected across northern areas. Also expect areas of fog
along the Downeast coast tonight through early Tuesday, with
patchy fog across the remainder of the forecast area. Low
pressure will lift northeast from the Great Lakes Tuesday,
drawing a cold/occluded front toward western New England late.
Moisture will persist in advance of the front keeping
cloudy/mostly cloudy skies across the forecast area, along with
the risk of isolated/scattered showers. Low temperatures
tonight will range from the lower to mid 50s north, to the upper
50s to around 60 Downeast. High temperatures Tuesday will range
from the mid to upper 60s north, to the upper 60s to around 70
Downeast.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Tuesday night expect an approaching well stacked system to be
pushing from Ontario into Quebec with a trailing warm occluded
front. A warm front will be over southern New England and will
remain over and south of the Gulf of Maine waters into Wednesday
AM. An approaching positively tilted trough will be digging over
the Great Lakes and shortwave energy will be rounding the bend
by late day. Warm and cloudy night with patchy fog expected Tue
Night into Wed AM with temps around 60F. Wednesday will feature
highs in the upper 60s to low 70s. By late day a rain band will
begin working into the FA from W to E ahead of the deep upper
500mb trof from the Great Lakes. Intially setting up over the
western zones before moving E through the night into Thu
morning. The upper trof will push through into Thursday morning
and take much of the day to get east of the area but the surface
front will move through in the AM. WPC continues a D3 excessive
rainfall outlook mainly in the "Marginal" category for much of
the FA except the Downeast coast. The "Slight" area makes it
into Northern Somerset county. Rainfall totals will be highest
along and northwest of the Longfellow Mtns where 1-1.5 inches
with isolated higher amounts are possible. Elsewhere, expecting
generally 0.5-1 inch but cannot rule out heavier amounts. Given
the soil moisture mainly in the 95th-99th percentile the chance
of isolated flooding remains possible especially in terms of
excessive runoff. This would mainly impact small creeks, streams
and urban areas. At this point widespread flooding isn`t likely.

&&

......LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Clearing skies over Central and Downeast areas with partly
cloudy skies across the north. Thursday night will be well
behind the cold/occluded front and upper trof with cooler
overnight low temps. Expecting Friday AM lows to be in the mid
to upper 40s north and low 50s south. High pressure ridging will
provide partly cloudy skies to the CWA on Friday for most of
the day with continued near seasonal normal high temps in the
upper 60s to low 70s.

High and mid clouds will then slowly spread S to N across the
FA Friday evening thru Saturday morning well in advance of Lee
as it continues to slowly move N across the western open
Atlantic. The consensus of long range models brings the western
periphery of the rain shield of Lee from SSE to NNW across the
FA beginning Sat afternoon and continuing Sat night into Sun
afternoon before any rain tapers to scattered showers Sun
afternoon with max PoPs capped at 50 percent over Downeast. The
actual track and impacts (if any) of Lee relative to our FA
remains under significant uncertainty at this time with a
considerable track spread by this coming weekend ranging as far
W from near Cape Cod MA and the Gulf of ME and as far E as Ern
NS. For now, we mention in the HWO to monitor latest NHC
advisories and forecast updates from this office as we approach
the weekend. There will be significant wave action due to long
period swells


Hazardous Weather Outlook
National Weather Service Caribou ME
344 PM EDT Mon Sep 11 2023

MEZ001>006-010-011-015>017-031-032-121945-
Northwest Aroostook-Northeast Aroostook-Northern Somerset-
Northern Piscataquis-Northern Penobscot-Southeast Aroostook-
Central Piscataquis-Central Penobscot-Southern Penobscot-
Interior Hancock-Central Washington-Southern Piscataquis-
Northern Washington-
344 PM EDT Mon Sep 11 2023

This Hazardous Weather Outlook is for Central Highlands Maine, Far
Eastern Maine, Far Northern Maine, Interior DownEast Maine, North
Woods Maine and Penobscot Valley Maine.

.DAY ONE...This afternoon and tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Locally heavy rainfall is possible for portions of the forecast area
from later Wednesday into Thursday morning, possibly resulting in
localized flooding.

Although the track, intensity, and impacts (if any) from Lee remain
uncertain at this time for our region, please monitor latest
National Hurricane Center advisories and forecast updates from WFO
Caribou heading into the weekend.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

$$


3:03 PM ADT Monday 11 September 2023
Tropical Cyclone Information Statement (Lee) in effect for:

Marine Zone
Maritime Waters
Browns Bank
East Scotian Slope
Georges Bank
LaHave Bank
Laurentian Fan
Sable
West Scotian Slope
This is the first official CHC information statement on Hurricane Lee.

The next information statement will be issued by 3 p.m. ADT Tuesday.

Lee could impact weather in Atlantic Canada this weekend as it moves northward from the tropics.  This initial bulletin is anchored to the offshore marine district south of Nova Scotia where the circulation of Lee would encroach upon first.

We are starting to get a better idea of how the weather will evolve this week over Atlantic Canada and the role Hurricane Lee may play.  Once the hurricane makes a northward turn by late Wednesday it will further enhance the tropical airmass over Atlantic Canada.  It will also have the effect of slowing the progress of a front which could increase the risk of heavy rainfall over the Maritime provinces during the latter part of the week.

We expect Lee's circulation to broaden significantly as it moves north later this week and there are no indicators at this time that the storm will be re-invigorated through merging with non-tropical weather systems.  Also it is possible the forward motion of the storm could slow which would permit further weakening over cooler waters before affecting land.  Given these factors, the storm would approach the region as a weak hurricane or strong tropical storm.  The range of track possibilities is very broad this far ahead in time, ranging from somewhere in Maine to the southeast of Nova Scotia.   

With the expanding size of the hurricane and a long trajectory northward, building surf conditions and rip currents are expected along the Atlantic coast of Nova Scotia this week and particularly on Friday.

This bulletin will be updated tomorrow with the latest forecast rationale.

Forecaster: Fogarty

Please continue to monitor alerts issued by the Canadian Hurricane Centre and forecasts issued by Environment Canada.

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